The post-copulation withdrawal response in female baboons: A functional analysis

Rapid withdrawal of females from males at the end of the copulatory sequence (prior to male dismounting) characterizes several primate species. The purpose of this paper is to make a preliminary investigation into possible functional aspects of these “copulatory darts.” Two hypotheses are proposed; (1) females use darts to aid competing males to locate the source of copulation calls; and (2) females dart in order to promote re-mating with the same male. Both hypotheses postulate that darts may thus enhance male-male competition, although acquisition of other benefits may be the primary drive to darting according to the re-mating hypothesis. Using data from 157 copulations collected from six females spread across four groups in a wild population of chacma baboonsPapio cynocephalus ursinus, darting behaviour is described. Within females, darting distance is highly variable. Darting distance is greatest at the time of ovulation (and maximal sexual swelling), and there is some evidence that darting may also be more frequent, and cover greater distances, when the mating male is adult rather than juvenile. While darting behaviour appears unrelated to the presence or absence of ejaculation, it tends to correlate positively with the duration of the female copulation call. These preliminary results are consistent with a mediating role in male-male competition and therefore provide support for both hypotheses.     

Developmental regulation of aldoxime formation in seedlings and mature plants of Chinese cabbage (Brassica campestris ssp. pekinensis) and oilseed rape (Brassica napus): Glucosinolate and IAA biosynthetic enzymes

The first steps in the biosynthesis of glucosinolates and indole-3-acetic acid (IAA) in oilseed rape (Brassica napus L.) and Chinese cabbage (Brassica campestris ssp. pekinensis) involve the formation of aldoximes. In rape the formation of aldoximes from chain-extended amino acids, for aromatic and aliphatic glucosinolate biosynthesis, is catalysed by microsomal flavin-containing monooxygenases. The formation of indole-3-aldoxime from l-tryptophan, the potential precursor of both indole-3-acetic acid and indolyl-glucosinolates, is catalysed by several microsomal peroxidases. The biosynthesis of glucosinolates and indole-3-acetic acid was shown to be under developmental control in oilseed rape and Chinese cabbage. No monooxygenase activities were detected in cotyledons or old leaves of either species. The highest monooxygenase activities were found in young expanding leaves; as the leaves reached full expansion and matured the activities decreased rapidly. The indole-aldoxime-forming activity was found in all of the tissues analysed, but there was also a clear decrease in foliar activity with maturity in leaves of rape and Chinese cabbage. Partial characterisation of the Chinese cabbage monooxygenases showed that they have essentially identical properties to the previously characterised rape enzymes; they are not cytochrome P450-type enzymes, but resemble flavin-containing monooxygenases. No monooxygenase inhibitors were detected in microsomes prepared from either cotyledons or old leaves.Abbreviations DHMet dihomomethionine - FMO flavin-containing monooxygenase - HPhe homophenylalanine - IAA indole-3-acetic acid - l-Phe l-phenylalanine - l-Trp l-tryptophan - MO monooxygenase - IAALD indole-3-acetaldehyde - IAOX indole-3-aldoxime - THMet trihomomethionine     

Functional analysis of the iron-stress induced CP 43′ polypeptide of PS II in the cyanobacterium Synechococcus sp. PCC 7942

Under conditions of iron-stress, the Photosystem II associated chlorophyll a protein complex designated CP 43, which is encoded by the isiA gene, becomes the major pigment-protein complex in Synechococcus sp. PCC 7942. The isiB gene, which is located immediately downstream of isiA, encodes the protein flavodoxin, which can functionally replace ferredoxin under conditions of iron stress. We have constructed two cyanobacterial insertion mutants which are lacking (i) the CP 43 apoprotein (designated isiA ^–) and (ii) flavodoxin (designated isiB ^–). The function of CP 43 was studied by comparing the cell characteristics, PS II functional absorption cross-sections and Chl a fluorescence parameters from the wild-type, isiA ^– and isiB ^– strains grown under iron-stressed conditions. In all strains grown under iron deprivation, the cell number doubling time was maintained despite marked changes in pigment composition and other cell characteristics. This indicates that iron-starved cells remained viable and that their altered phenotype suggests an adequate acclimation to low iron even in absence of CP 43 and/or flavodoxin. Under both iron conditions, no differences were detected between the three strains in the functional absorption crossection of PS II determined from single turnover flash saturation curves of Chl a fluorescence. This demonstrates that CP 43 is not part of the functional light-harvesting antenna for PS II. In the wild-type and the isiB ^– strain grown under iron-deficient conditions, CP 43 was present in the thylakoid membrane as an uncoupled Chl-protein complex. This was indicated by (1) an increase of the yield of prompt Chl a fluorescence (F_o) and (2) the persistence after PS II trap closure of a fast fluorescence decay component showing a maximum at 685 nm.Abbreviations Chl chlorophyll - CP 43, CP 47 and CP 43 Chl a binding protein complexes of indicated molecular mass - DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - F_m and F_m fluorescence when all PS II reaction centers are dosed in dark- and light-acclimated cells, respectively - F_o fluorescence when all PS II reaction centers are open in dark acclimated cells - F_v variable fluorescence after dark acclimation (F_m–F_o)     

An unusual Group 2 LEA gene family in citrus responsive to low temperature

Six cDNAs representing unique cold-induced sequences have been cloned from the hardy citrus relative Poncirus trifoliata. Among these, pBCORc115 and pBCORc119 were found to belong to the same gene family. Sequencing data indicated that pBCORc115 and pBCORc119 each contained an open reading frame, coding for a 19.8 kDa protein (COR19) and a smaller 11.4 kDa protein (COR11) respectively. Inspection of the deduced amino acid sequences revealed three large repeats in COR19, but only one was present in the COR11. Two elements: a Q-clustered tract and a K-rich motif were identified in each repeat. The K-rich motifs were similar to those of cotton D-11 and Group 2 LEA proteins. A Serine-cluster, a common feature in many Group 2 LEA-like proteins, was also found in these proteins, but it was in an unusual position at the carboxy-terminus. A bipartite motif of basic residues, similar to known nuclear targeting sequences, was also present in COR19 and COR11, suggesting that members of this protein family may have a nuclear targeting function. The expression of COR19 mRNA in response to cold acclimation, drought, flooding, and salinization was examined. COR19 expression in leaf tissue was induced in response to cold acclimation, but repressed during drought and flooding stress.     

Sensitivity to stress in the bivalve Macoma balthica from the most northern (Arctic) to the most southern (French) populations: low sensitivity in Arctic populations because of genetic adaptations?

The stress sensitivity, determined in copper exposureexperiments and in survival in air tests, and thegenetic structure, measured by means of isoenzymeelectrophoresis, were assessed in populations of theBaltic clam Macoma balthica (L.) from itssouthern to its northern distribution limit, in orderto test the hypotheses that near the distributionlimit the clams would be more stress sensitive andwould have a lower genetic variability. Thepopulations in west and north Europe show a stronggenetic resemblance. The populations in the sub-ArcticWhite Sea are genetically slightly different, and showa low stress sensitivity. The populations in theArctic Pechora Sea are genetically very distant fromthe other populations, and show the lowest stresssensitivity. Near the southern distribution limit, inagreement with the hypotheses, genetic variability islow and stress sensitivity high. On the other hand, incontrast to expectation, near the northerndistribution limit, in the populations of the PechoraSea, the genetic variability was higher, thus notreduced, and the stress sensitivity was low comparedto all other populations. Yet, it remains a questionif such is due to gradual physiologicalacclimatization (and ongoing differential selection)or to genetic adaptation.     

Sugar beet guard cell protoplasts demonstrate a remarkable capacity for cell division enabling applications in stomatal physiology and molecular breeding

A highly-efficient protocol for the large-scale isolation ofguard cell protoplasts from sugar beet (Beta vulgaris L.) hasbeen developed. Optimization of conditions for culturing theseprotoplasts resulted in extensive cell division and colony formation,at frequencies exceeding 50%. Plants can subsequently be regeneratedfrom these guard cell-derived colonies. This provides definitiveconfirmation that, in sugar beet leaf protoplast populations,only guard cells are the source of totipotent protoplasts. Thesefindings are the outcome of a directed, non-empirical approachto overcoming plant cell recalcitrance which was initiated byexploiting computer-assisted microscopy to couple in vitro responseto cell origin. The results reaffirm the conclusion that, inplants, extreme degrees of cytodifferentiation need not entailterminal specialization. The responsive nature of this systemcan be ascribed to the unique use of cultures essentially comprisinga single in vivo cell type. A uniform model system has thusbeen created with potential for widespread application. Theirdistinct morphological (and mechanical) features make guardcells a valuable choice for studying various fundamental aspects,not only of stomatal physiology, but also of plant cell (de)differentiation,differential gene expression etc. Furthermore, an applied valuefor such a system can also be envisaged. Results indicate thatthese cells are highly amenable to genetic manipulation techniques.The importance of these observations to our understanding ofplant cell function and behaviour is discussed. Key words: Beta, guard cells, stomatal physiology, totipotency, transformation     

Restriction polymorphisms of the ceruloplasmin gene on chromosome 3

Using a probe isolated from a human liver cDNA library, polymorphisms were observed in the human ceruloplasmin gene with the enzymes PstI and MspI. The PstI polymorphism was frequent (allele frequencies, 0.46 and 0.54) whereas the polymorphisms found with MspI were rare.     

Excess of deletions of maternal origin in the DiGeorge/Velo-cardio-facial syndromes. A study of 22 new patients and review of the literature

We have determined the parental origin of the deleted chromosome 22 in 29 cases of DiGeorge syndrome (DGS) using a CA-repeat mapping within the commonly deleted region, and in one other case by using a chromosome 22 short arm heteromorphism. The CA-repeat was informative in 21 out of 29 families studied and the deleted chromosome was of maternal origin in 16 cases (72%). When these data are pooled with recent results from the literature, 24 de novo DGS, velo-cardio-facial syndrome (VCFS) and isolated conotruncal cardiac disease deletions are found to be of maternal origin and 8 of paternal origin, yielding a ² of 8 with a probability level lower than 0.01. These data, and review of the literature on familial DGS/VCFS and isolated conotruncal cardiopathies suggest that there is a strong tendency for the 22q11.2 deletions to be of maternal origin.